The present invention relates to the general technical field of the filtration of fluids, and in particular water, by passage of the fluid to be treated through a substrate whose physico-chemical properties assure the treatment of impurities contained in the fluid.
The present invention concerns, more specifically, a device for purifying fluids, and particularly but not exclusively an apparatus for filtering water, comprising a reservoir for fluid to be treated associated with a pump means adapted to cause the fluid which is to be treated to be circulated through a filtration means from the lower part of that means toward its upper part, and then to an element for dispensing the treated fluid.
It is already known to purify fluids, in particular drinking water, by passage of the water on a substrate which assures a filtration having an physico-chemical character.
Thus, U.S. Pat. No. 3,950,253 discloses a domestic water purification apparatus comprising a reservoir for water to be treated and in which is disposed a filter cartridge intended to assure the treatment and purification of the water. The apparatus also includes a pump adapted to pump the water to be treated in order to direct it, through the intermediary of a tubing, toward the bottom of the filter cartridge in a manner to cause the water which is to be treated to circulate in the cartridge from the bottom to the top. The water, after having been treated and purified, thus exits the upper part of the filter cartridge via a dispensing tube whose end opens into a stationary receptacle integrated into the body of the purification apparatus.
The constituent materials of the filter cartridge are constituted, in a manner known per se, of a mixture of activated carbon with a silver salt additive to combat bacterial growth, and ion exchange resin. Various other constituents can be added to the filter cartridge when specific impurities are present in the water to be treated.
Such an apparatus provides a non-negligible solution to the specific problem of purification and treatment of water for domestic use in a given environment. Running water can, in effect, be rid, entirely or in part, by the expedient of the filter cartridge, of the principal contaminating agents of the organic or inorganic types such as chlorine, lead, pesticides, heavy metals, nitrates, etc., which are the cause of disagreeable flavors, odors or colors.
It has been found, however, that the purification of water in such an apparatus is not effected in a complete manner, regardless of the nature and quality of the composition forming the filter cartridge. In effect, one observes particularly a progressive diminution in time of the effectiveness of the purification linked at the same time to the progressive plugging of the filter cartridge on the one hand, and to a diminution of the intrinsic effectiveness of the cartridge because of a decrease in its biologic activity, on the other hand. Such a decrease in activity can be related to the vertical position of the filter cartridge leading, during periods of non-use, to a progressive drying of the filter cartridge by evacuation of the water under the influence of gravity. It must be equally noted that the mounting of the filter cartridge at the very interior of the reservoir of liquid which is to be treated renders the operation of replacing the filter cartridge difficult, such a replacement necessitating moreover a series of difficult manipulations which multiply the zones of contact between the hands of the user and the apparatus. As a result, it becomes difficult to completely master the state of cleanliness of the apparatus and to effectively battle against the development of concentrations of bacteria in zones which are difficult to clean.